There is an oil sump in the bottom of the oil pan that has a mesh screen on it. The idea is to let metal particles separate out of the suspended oil and collect in the sump, rather than circulate through the engine. No, that is not a "regular maintenance item" and I doubt anyone ever breaks it down to clean it. I have never heard of a "forward cam screen". That sounds a like you also need to rotate your muffler bearings diagnosis.
Unfortunately, front cylinders tend to wear out on these bikes and nobody knows why. When mine popped, it was the front cylinder as well. Interestingly enough, mine gave up the ghost at 38k, yours failed at 33k. Notice the pattern?
The engine is also not serialized, so you can use any engine from any year bike without affecting your title.
Now, here's what I would suggest. Have the dealership swap the engine, then start shopping for a new bike. You bought someone else's problem child and now you're going to have step-problem child problems with the new engine. They're great bikes for the money, but there are better options out there.